Class 8 Direct And Inverse Proportions CBSE Questions & Answers

Class 8 · Direct And Inverse Proportions

This is Mathematics Class 8 Direct and Inverse Proportions CBSE Questions & Answers. There are 15 questions in this test with each question having around four answer choices.

Questions & Answers

1
If two quantities x and y vary directly, then
  • A
    \({\text{x}}-{\text{y}}\) is constant
    Correct
  • B
    \({\text{x}} + {\text{y}}\) is constant
  • C
    \({\text{x}} \times {\text{y}}\) is constant
  • D
    \({\text{x}}/{\text{y}}\) is constant
2
If two quantities x and y vary inversely then
  • A
    \({\text{x}} + {\text{y}}\) is constant
  • B
    \(\frac{x}{y}\) is constant
  • C
    \({\text{x}} \times {\text{y}}\) is constant
  • D
    \({\text{x}}-{\text{y}}\) is constant
    Correct
3
If 8:12::6:a, the value of a is
  • A
    8
  • B
    9
    Correct
  • C
    12
  • D
    10
4
If\({\text{16}} \times {\text{9}} = {\text{12}} \times {\text{m}}\), the value of m is
  • A
    16
  • B
    12
    Correct
  • C
    9
  • D
    None of these
5
If the cost of 18 pens is Rs. 234, a dozen pen will cost
  • A
    Rs 144
  • B
    Rs 192
  • C
    Rs 156
    Correct
  • D
    Rs 180
6
Raju earns Rs 1440, if he works for 12 days. If he works for 30 days, he will earn
  • A
    Rs 4800
  • B
    None of these
  • C
    Rs 3600
    Correct
  • D
    Rs 2400
7
A tree of 20m height casts a shadow 8 m long, what is the height of a tree that casts a shadow 10 m long
  • A
    15 m
  • B
    25 m
    Correct
  • C
    20 m
  • D
    None of these
8
There is enough food to last for 40 people for 10 days. If 10 more people join them, the food will last for
  • A
    None of these
  • B
    8 days
    Correct
  • C
    12 days
  • D
    10 days
9
A car is traveling at a speed of 54 km/ hour, covers a distance in 2.5 hours. At a speed of 45 km/hr, it covers the same distance in
  • A
    2 hours
  • B
    1 hour
  • C
    None of these
  • D
    3 hours
    Correct
10
25 labourers can build a wall in 4 days. IF only 20 labourers report for work, the wall be built in
  • A
    6 days
  • B
    None of these
  • C
    3 days
  • D
    5 days
    Correct
11
When one quantity is increased, the other quantity is also increased. This proportion is called .....................
  • A
    Kally proportion
  • B
    Direct proportion
    Correct
  • C
    None of these
  • D
    Inverse proportion
12
If a and b vary inversely, find the value of x.
Question 12 figure 1
  • A
    6
  • B
    4
    Correct
  • C
    None of these
  • D
    5
13
72 books are packed in 4 cartons of the same size. How many cartons are required for 360 books?
  • A
    22
  • B
    18
  • C
    20
    Correct
  • D
    None of these
14
If 36 men can complete a work in 24 days, how many extra men be employed so as to complete the work in 18 days?
  • A
    12
    Correct
  • B
    None of these
  • C
    6
  • D
    24
15
A garrison of 300 men had provision of food for 50 days. A reinforcement of 200 men arrived. Find the number of days for which the food will last.
  • A
    30
    Correct
  • B
    None of these
  • C
    20
  • D
    40